This invention relates to the field of devices for lifting and centering doors for the purpose of hanging to a door frame or door jamb. Within this broad field the invention is particularly directed for use with unusually heavy doors such as the heavy metal doors used for cell blocks which weigh between 140 to 175 pounds, for lead shield doors for use in hospitals which weigh as much as 200 to 300 pounds as well as being unusually wide, sometimes up to four feet, as well as being unusually high, sometimes up to seven or eight feet, and other unusually heavy doors of this type. Some of these unusually heavy doors also have other characteristics which make them more difficult to hang than ordinary doors. For example, the heavy metal doors used in cell blocks of prisons include hinge members which do not have removable hinge pins. Therefore, the holes in the hinge member which is to be bolted to the door frame have to be lined up precisely with the corresponding holes in the door frame in order to insert and secure the bolts or screws which are used to hold the hinge member to the door frame.
Prior art devices which have been used to lift, center and otherwise facilitate hanging of doors include the door brace disclosed in U.S. Pat. No. 4,141,192, the wedging tool disclosed in U.S. Pat. No. 3,021,112, a household utility jack disclosed in U.S. Pat. No. 2,910,270, the door hanger and trolley disclosed in U.S. Pat. No. 2,503,388 and the cleaving wedge disclosed in U.S. Pat. No. 1,407,719.
The devices known to the prior art for use in lifting, centering and otherwise facilitating the handing of doors are complicated and cumbersome affairs and many are adapted for use only with particular types of doors. The door lifting and centering device in accordance with the present invention is a relatively simple and sturdy device which can be used universally with doors of all types and it includes the feature of an elongated operating member whereby the installer does not have to bend over or stoop in order to operate the device.